Exposure of Protected and Unprotected Forest to Plant Invasions in the Eastern United States

Kurt Riitters,Songlin Fei,Christopher Oswalt,Basil Iannone,Kevin Potter,Qinfeng Guo

doi:10.3390/f9110723

Abstract

Research Highlights: We demonstrate a macroscale framework combining an invasibility model with forest inventory data, and evaluate regional forest exposure to harmful invasive plants under different types of forest protection. Background and Objectives: Protected areas are a fundamental component of natural resource conservation. The exposure of protected forests to invasive plants can impede achievement of conservation goals, and the effectiveness of protection for limiting forest invasions is uncertain. We conducted a macroscale assessment of the exposure of protected and unprotected forests to harmful invasive plants in the eastern United States. Materials and Methods: Invasibility (the probability that a forest site has been invaded) was estimated for 82,506 inventory plots from site and landscape attributes. The invaded forest area was estimated by using the inventory sample design to scale up plot invasibility estimates to all forest area. We compared the invasibility and the invaded forest area of seven categories of protection with that of de facto protected (publicly owned) forest and unprotected forest in 13 ecological provinces. Results: We estimate approximately 51% of the total forest area has been exposed to harmful invasive plants, including 30% of the protected forest, 38% of the de facto protected forest, and 56% of the unprotected forest. Based on cumulative invasibility, the relative exposure of protection categories depended on the assumed invasibility threshold. Based on the invaded forest area, the five least-exposed protection categories were wilderness area (13% invaded), national park (18%), sustainable use (26%), nature reserve (31%), and de facto protected Federal land (36%). Of the total uninvaded forest area, only 15% was protected and 14% had de facto protection. Conclusions: Any protection is better than none, and public ownership alone is as effective as some types of formal protection. Since most of the remaining uninvaded forest area is unprotected, landscape-level management strategies will provide the most opportunities to conserve it.

Highlights

Protected areas such as parks and forest reserves are important components of natural resources conservation
We estimated that 16.1 Mha (10.3%) of the total 157.0 Mha of forest in the study area was protected according to IUCN standards (Table 2)
For the forest that was not labeled by an IUCN category, we estimated that 123.7 Mha (88%) was privately owned and 17.2 Mha (12%) was publicly owned (Table 3)

Summary

Introduction

Protected areas such as parks and forest reserves are important components of natural resources conservation. Motivated to preserve unique or irreplaceable resources, protected areas later became the centerpiece of global strategies to conserve biodiversity while promoting other socio-ecological values such as sustainable development, carbon sequestration, and water quality [1]. As of 2009, 13% of the global terrestrial area was “formally protected” according to IUCN Union for Conservation of Nature) standards [2], of which approximately half had “strict protection for biodiversity” [3]. There is no doubt that attention must be given to the threats that degrade ecological integrity which is the foundation for biodiversity [2,11,12,13]

Methods

Results

Discussion

Conclusion